In exercise 6, data were given on the proportion of games won, the number of team home runs, and the earned run average for the team’s pitching staff for the 16 teams in the National League for the 2003 Major League Baseball season (USA Today website, January 7, 2004).

a. Did the estimated regression equation that uses only the number of home runs as the independent variable to predict the proportion of games won provide a good fit? Explain.

b. Discuss the benefits of using both the number of home runs and the earned run average to predict the proportion of games won.